Typical computer systems, especially computer systems using graphical user interfaces (GUIs), are optimized for accepting user input from one or more discrete input devices, such as a keyboard for entering text, and a pointing device, such as a mouse with one or more buttons, for operating the user interface. An example of such a GUI is the user interface for the WINDOWS® computer operating system (available from Microsoft Corporation of Redmond, Wash.). The ubiquitous keyboard and mouse interface provides for fast creation and modification of documents, spreadsheets, database fields, drawings, photos, webpages, and the like.
Recently, however, pen-based computing systems, such as tablet PCs, personal digital assistants, and the like, have been increasing in popularity. In pen-based computing systems, user input advantageously may be introduced using an electronic “pen” or stylus (e.g., akin to writing with a pen or pencil on a piece of paper). Indeed, in at least some pen-based computing systems, all user input is capable of being entered and manipulated using an electronic pen input device, and the user interface is fully controllable using only the electronic pen.
Radial menus, as used with user interfaces on a desktop or laptop computer system, are increasingly being used with these pen based computing systems. Radial menus allow menu options to be selected using a pointing device, such as a mouse or electronic pen, from a circular display of options that may, upon activation, appear anywhere within the user interface. As the number of menu items within the radial menu increases, the size of each menu option selection area decreases. The small selection area of menu options may lead to erroneous menu selections. Improved sizing of menu option selection areas would benefit users of these menu interfaces.